1. Field of the Invention
The present invention relates to an observation apparatus and an observation method for observation of a specific region of a specimen.
2. Description of the Related Art
One conventional technique of microscopy of a specimen, such as a living cell, includes capturing an image of the specimen at time intervals (hereinafter such a manner of image-taking will be referred to as time lapse imaging) to generate an observation image, and reproducing a series of observation images after the time-lapse imaging is finished, thereby observing a moving picture to check a morphological change in the specimen over time. Such a conventional technique is considered to be highly effective for an observation of temporal change in the specimen.
In recent years, the time lapse imaging is sometimes performed at plural imaging positions, for example, when living cells cultured under the same condition are tested with plural types of agents for confirmation of the effect of the agents, or when temporal changes of different cells are observed under the same environment.
When the time lapse imaging is performed at plural imaging positions (this manner of image-taking will be hereinafter referred to as multipoint time lapse imaging), the plural imaging positions are not always located in a viewing field of one microscope. Even if the imaging positions reside on one particular living cell under the observation, one or more imaging positions are often located outside the viewing field of the microscope. In addition, plural imaging positions often reside respectively on different living cells.
One conventional imaging technique to accommodate the inconveniences described above is described in Japanese Patent Application Laid-Open No. 2002-277754 (KOKAI). A structure and a method described in JP-A No. 2002-277754 (KOKAI) allow for the multipoint time lapse imaging. The described method includes steps of placing a specimen containing living cells on a stage whose positioning is electrically controllable along X, Y, and Z axes, and previously setting positional coordinates of plural imaging positions, exposure of an imaging element at the imaging positions, a time interval of the time lapse imaging for each imaging position, and the number of images to be captured.
When the multipoint time lapse imaging is performed, a screening is performed to set the imaging positions before an actual imaging starts. Conventionally, during the screening, a specimen, i.e., living cells are irradiated with an exciting light, a live image of the specimen is displayed, and an operator sets the imaging positions while looking at the live image.
While the live image is displayed for the screening, the living cells are kept irradiated with the exciting light. The irradiation with the exciting light, however, causes discoloration and damages of the living cells, and preferably be suppressed as far as possible.